The lyophilizer (
Say again: vacuum freeze drier)
Of mostly use of two kinds of pump, vacuum pump is a kind of rotary vacuum pump oil seal type, the other is a roots pump, also known as mechanical booster pump, some of the lyophilizer using a two stage rotary vane vacuum pump, which can reach the requirement of the vacuum degree, some of the lyophilizer using a single stage work together with roots pump, oil pump use effect is basically the same two ways.
oil seal type vacuum pump should be high speed straight league pump, its small size, large pumping speed, and should not be belt drive vacuum pump, roots pump also should be straight association-like, and should not be the belt drive, the best is the hydraulic transmission type, this kind of roots pump can under atmospheric pressure and oil seal type vacuum pump to start at the same time.
Some of the lyophilizer requires the use of oil-free vacuum pump.
circulating pump should be shielded, because it does not happen leak phenomenon, straight league pump oil seal, may produce the oil.